• 将Base64转为Blob类型

parseFileType: function(basestr, type) {
  var text = window.atob(basestr.split(',')[1]);
  var buffer = new Uint8Array(text.length);
  for (var i = 0; i < text.length; i++) {
    buffer[i] = text.charCodeAt(i);
  }
  var blob = self.getBlob([buffer], type);
  return blob;
}

• 获取Blob对象的兼容性写法

getBlob: function(buffer, format) {
  try {
    return new Blob(buffer, {
      type: format
    });
  } catch (e) {
    var bb = new(window.BlobBuilder || window.WebKitBlobBuilder || window.MSBlobBuilder);
    buffer.forEach(function(buf) {
      bb.append(buf);
    });
    return bb.getBlob(format);
  }
}

获取到 blob 后可以做图片上传。